The Arabic legacy of science and philosophy has long been obscured in the West, even though the medieval Islamic world's myriad scientific innovations preceded—and in many ways enabled—the European Renaissance. Arab astronomers laid foundations for the heliocentric model of the solar system long before Copernicus; physicians accurately described blood circulation and the inner workings of the eye long before Europeans solved those mysteries; physicists made discoveries that laid the foundation for Newton's theories of optics. But the most significant aspect of Middle Eastern science was its evidence-based approach, a legacy that British-Iraqi nuclear physicist Jim al-Khalili explores here to fascinating effect.